Halogenated ortho-sulpho-benzoic acid compounds



Patented May 27, 1930 UNITED STATES PATENT OFFICE DANIEL TWISS, OFBALTIMORE, MARYLAND, ASSIGNOR TO HYNSON, WESTCOTT & DUN NING, INQ, OFBALTIMORE, MARYLAND, A CORPORATION OF MARYLAND v a J HA-LOGENATEDORTHO-SULPHO-BENZOIC ACID COMPOUNDS No Drawing.

This invention relates to mono-, di-, tri-, and tetrahalogenatedortho-sulpho-benzoic acid compounds which are useful as intermediates inthe preparation of dyes, and to processes for preparing the same. Morespecifically, this invention relates to diand tetrahalogenatedortho-sulpho-benzoic acid anhydrides.

The discovery was made that the anhydride of osulpho-benzoic acid, thefree acid itself and its salts, for instance the acid ammonium salt, canbe readily halogenated in fuming sulfuric acid to form mono-, di-,triand tetrahalogenated o-sul-pho-benzoic acid anhydrides. According tothis process it is also possible to prepare mixed halogenatedo-sulpho-benzoic acids or anhydrides by subsequent halogenation of apartially halogenated acid, using a different halogen.

The amount of SO present in the reaction mixture as well as the amountof halogen used is an important factor in determining the eX- tent andfacility of halogenation, e. g., in preparing a tetrahalogenatedderivative a certain amount of 60% oleum may be re- 1 placed by agreater amount of 50% oleum containing an equivalent amount of S0 andthe same number of halogens introduced thereby. For partiallyhalogenated acids, i. e., a dihalogenated derivative correspondinglysmaller amounts of oleum may be used. The monoand trihalogenatedderivatives may also be prepared by using a suitable amount of SO, andhalogen. I do not wish to be limited to any particular position of thehalogen in the nucleus, as this is not definitely known.

The o-sulpho-benzoic acid, its anhydride or its salt, is dissolved infuming sulfuric acid, heated in an oil bath preferably at about 60 100C., and the halogen slowly added. As an accelerator a small amount ofiodine is used, which, however, is not essential. After the requiredamount of halogen has been added, the reaction is terminated byelevating the oil bath temperature to about 150- 170 C. After coolingthe halogenated 0- sulpho-benzoic acid anhydride precipitates and can beseparated from the remaining sulfuric acid by direct filtration or bymix- Application filed April 4, 1928. Serial No. 267,483.

ing with ice water and filtering at a low temperature. The anhydride canbe freed from adhering sulfuric acid by Washing with glacial aceticacid. On standing at room temperature the anhydrides go overinto theacids.

The halogenation is illustrated by the following equations:

Chlorination of the free acid:

0 H COOH+5 so +8 01 c 01 0 A0 HSO 0480311 3 e| SOl +la-b24 Brominationof the free acid:

0 H C00H+5 so +4 B c B o 2s0 Hso r= r 3 04803 1 I o4SO/+ z 24Bromination of the acid ammonium salt:

coon 2'CaH4 +8 Bt+10 S03= SOaNH4 co 2C6BH o+mnmsoi+snzsoi+4 so? soBromination of the anhydride:

The iodination is similar to the bromination.

Example .1. Tetrachloro-suZp/to-benzoz'c acid anhyohide Fifty grams ofo-s ulpho-benzoic acid (or v ing sulfuric acid or an amount of 50%fuming sulfuric acid containing an equivalent amount of S0,. The mixtureis heated in an oil bath at 60 (1, two grams of iodine are added and aslow current of chlorine is passed through the solution until no morechlorine is absorbed. The reaction is terminated by heating the oil bathat about C. After cooling the tetrachlor-o-sulpho-benzoic acid anhydrideis filtered from the remaining sulfuric acid.

Example 2. Teh' abrom-o-sulpko-benzoic acid I v anhydflde Fifty fivegrams of o-sulpho-benzoic acid are dissolved in three hundred and fiftygrams of 60% fuming sulfuric acid, the mixture is heated in an oil bathat 8085 C., and 33 cc. of bromine are gradually added. Two to threegrams of iodine may be added as a catalyst. The reaction is terminatedby raising the temperature of the oil bath to l60170 C. After coolingthe/tetrabrom-osulpho-benzoic acid anhydride is isolated asdescribed-above. Instead of o-sulpho-benzoic acid, its anhydride or itsacid ammonium salt may be used following exactly the same procedure.

Emample 5. Tetmz'odo-o-sulpho-benzoic acid anhydrideTetraiodo-o-sulpho-benzoic acid is isolated as described before.

Example 4.'Dz'brom-0-sulpho-benzoic acid anhydride One hundred and tengrams of o-sulphobenzoic acid are dissolved in four hundred grams ofabout 35% fuming sulfuric acid.

Two grams of iodine are added and then gradually 37 cc. of bromine. Thetemperature of the oil bath is kept at about 80-85 C. during theaddition of the bromine, then heated up to 150160 C. to terminate thereaction. After cooling the reaction mass is poured onto ice and theprecipitated dibromo-sulpho-benzoic acid anhydride is filtered at a lowtemperature. 4 At room temperature the anhydride goes over into theacid.

EazampZe 5L Dz'iodo-o-sulpho-benzoz'c acid anhydride 1 One hundred andtwenty grams of o-sulpho-benzoic acid are dissolved in four hundredgrams of 35% fuming sulfuric acid and one hundre'd and twenty grams ofiodine are 7 added. The diiodo-o-sulpho-benzoic acid is isolated asdescribed in the preceding examples. I

The di-chl9r-o-su1pho-benzoic acid may be prepared by the sameprocedure. v In the appended claims, theterm orthosulpho-benzoic acidcompound is used to designate the group consisting of itself, its

anhydride and its salts, especially the acid ammonium salt.

.I claim:

1. A nuclear polylialogenated orthosulphO-benzoic acid compound. 2.- Anuclear polyh' logenated, Orthosulpho-be'nzoic acid anhydride.

3. A nuclear polyhalogenated orthosulpho-benzoic acid anhydride havingthe formula:

orthowherein X stands for hydrogen or iodine, two or four Xs beingiodine.

9. A tetraiodo ortho-sulpho-benzoic acid compound.

' 10. Tetraiodo ortho-sulpho-benzoic acid anhydride. I 11. Process ofpreparing halogenated ortho-sulpho-benzoic acid compounds whichcomprises treating an ortho-sulpho-benzoic acid compound with a halogenin fuming sulfuric acid.

12. Process of preparing halogenated ortho-sulpho-benzoic acid compoundswhich comprises treating a-n ortho-sulphO-benzoic acid compound with ahalogen in fuming sulfuric acid at temperatures between about 60-17 0 C.

I 13. Process of preparing halogenated ortho-sulpho-benzoio acidanhydrides which comprises treating ortho-sulpho-benzoic acid with ahalogen in fuming sulfuric acid.

14. Process of preparing halogenated ortho-sulpho-benzoic acidanhydrides which comprises treating ortho-sulpho-benzoic acid with ahalogen in fuming sulfuric acid at temperatures between about 60170 G.

15. Process of preparing tetraiodo orthQ- sulpho-beirzoic acid anhydridewhich comprises treating ortho-sulpho-benzoic acid with iodine in fumingsulfuric acid.

In testimony whereof, I affix my signature.

DANIEL TWISS.

